Introduction

LM334 is a constant current source. When there is some voltage across the terminals, the device will “limit” the current through the terminals. Therefore, the device can be placed anywhere in the circuit, as long as there is a sufficient voltage margin.

Connection

Bias the constant current source by connecting a resistor between R and V- terminals. The current could be determined by equation (3) in the LM334 Datasheet (please click the link and calculate by yourself).

Further Readings

https://electronics.stackexchange.com/questions/332246/understanding-the-necessity-of-tail-current-source-in-differential-amplifier-sim